Arc-lamp electrode.



M. H. BAKER.

ARC LAMP ELECTRODE.

APPLICATION FILED OCT. 22. 1909. RENEWED APR. 23. 1914.

1,1 1 8,4164, Patented Nov. 24, 1914.

WITNESSES.- INVENTOR. flZM M macaw/ 5mm Zia/2Z1 w a Y A17 ORNE Y.

H15 nuwins PETFQS 120.. FHOTO LITHO WASHING rc N. Dv c UNITED STATESPATENT OFFICE.

MALCOLM H. BAKER, OF BOSTON, MASSACHUSETTS, ASSIGNOLR. TO AMERICANFLAMING ABC LAMP COMPANY, A CORPORATION OF MASSACHUSETTS.

ARC-LAMP ELECTRODE.

Application filed October 22, 1909, Serial No. 523,990.

To all whom it may concern:

Be it known that I, IVIALCOLM H. Bimini,

a citizen of the United States, and a resident of Boston, in thecounty'of Suffolk and Commonwealth of Massachusetts, have inventedcertain new and useful Improvements in Arc-Lamp Electrodes,1of which thefollowing is a specification.

My invention. refers particularly to the type of electrode having alongitudinal metallic feed'regulating strip secured thereto, the saidstrip being adapted to operatively engage at its lower end with alateral support, and thus to permit a downward feed of the electrode asthe said strip is fused by the heat of the arc, the said feed regulatingstrip being attached. to the electrode in any I metal in the feed strip.

suitable manner. Long continued experiment with this type of electrodeshows it to be of gr at advantage to limit the amount of \Vhile suchelectrodes, and particularly flaming arc electrodes, are usuallyprovided with an internal metallic wire to reduce ohmic resistance, andwhile a metallic feed strip longitudinally attached thereto serves alsoas a current conductor through'the electrode, yet its necessary crosssection as afeed strip greatly eX- ceeds that required as a currentconductor. The introduction of this relative increase of metallic massin the feed strip tends to introduce disturbance in the operativeburning of the electrode. For this reason, I have found it advantageousto limit the amount of metal in the feed strip as much as possible. Suchfeed strips, in general, operate in cooperation with a support uponwhich they rest during their gradual fusion. The radial dimension of thestrip can not be limited beyond a point which gives a safe engagementbetween the said strip and the support. To limit the mass as desired Ihave, therefore, found it desirable to limit its thickness to the lowestpracticable dimensions. For instance, I may employ a strip having athickness of about .006 inches, but such a strip, particularly of ametal of low fusibility and of a low annealingpoint, such as aluminumwhich has been found well. adapted for the purpose, and whichIpreferably employ, may be, and generally is, subjected to the heateffects of the are for a considerable distance up from the point ofsupport; and the said strip, carryingas it may the weight of theelectrode or of inter- Patented Nov. 24, 1914.

Renewed April 23, 1914. Serial No. 833,977.

. connected electrodes, tends to collapse sidewise at or near the saidpoint of support, and thus to produce an over feed of the elec trode.This chance of collapse of the feed strip isnotably present in aluminum,on a count of the low tennierature at which this metal anneals,aloout500 F., although its fusing point is 1100 F.,and for this reason astiffening formation for the portion of the said aluminum exterior tothe elec-- trode is practically an inherent necessity. I have sought,therefore, not only to limit the amount of metal in the strip, and toinsure its firm union with the electrode, but

' particularly to limit the amount of metal exterior to the electrode,and to so form this exterior portion as to strengthen it laterally, andthereby to minimize the chance of strip collapse and consequentirregularity of feed, or over feed. To accomplish this result, I havedeveloped the forms of feed strips herein shown, all of which, while ofvery thin cross section interior to and at the line of union with theelectrode, are given a stiffening formation exterior to the saidelectrode, and as a preferable form, I have, after long experiment,devised and adopted a form which has the same thin cross section, butwhich, by means of corrugations, preferably regular longitudinally ofthe strip, is stiffened to a marked degree and yet without theintroduction of more metal to accomplish this result. The object of thiscorrugation, or its equivalent, is, otherwise expressed, to maintain aconstant radial alinement-between the electrode slot and the feedgoverning strip, and the said corrugation may he applied either beforeor after the strip is locked in place in the electrode, but, as aconvenient manufacturing method, I prefer to cut the feed strip fromtiin metal of uniform gage, and to give to the outer and inner edgeseach a corrugating formation, the outer corrugation being for thepurpose of stiffening the strip, and the inner corrugation being for thepurpose of locking the strip securely within the electrode slot when thesaid strip is drawn there through. Instead of corrugating the outer edgeof the strip, I may bend, fold, or otherwise distort it, or I may merelyplace a series of indentations along the edge, the sole object being togive rigidity to the por-' tion of the strip projecting outside of thebody of the electrode. I may also roll or press the strip of metal intothe shape of I beam or other equivalent shape and thereby obtain boththe electrode locking and exterior stiffening results, but 1 preIer touse metal of unirorm thickness as first described, in order to employ aminimum amountof the said metal.

l have illustrated my invention in the an. nexed drawings, inwhichbigure l is an elevatlon of a complete electrode provided with myimproved .feed

pressed into the iorm of an I beam. In the figures, 1 1s the main orcentral portion of the strip, 2 the inner longitudinal edge which locksin the electrode slot, and 3 the outer longitudinal or stifiening edge.The electrode appears at i and the electrode slot at 5. I

In actual practice I have found, with the electrodes of ordinarycommercial length,

from 400 to 650 millimeters, that improved results are had byeliminating the usual internal conducting wire and causing its functionto be periormed by. the feed strip. When the support and strip areproperly arranged, I further find that about 80 per cent. of the. totalmetallic mass of the strip is retained above the support and is thusprevented from entering the are.

I claim as my inventionz 1. An arc lamp electrode provided with anexternal longitudinal metal extension,

the said extension being given a stifiening iormation substantiallyalong lts outer lon- -jgitudinal edge and entirely outside of theelectrode. i

2. An arc lamp electrode having a lonv gitudinal externally projectingmetal feed regulating extension 'operatively attached thereto, theportion of said extension exterior to the electrode having a stiffeningformation relatively stifier than said strip at its junction with theelectrode.

3. An arc lamp electrode having, in com bination with a main-electrodeportion pro- VlClGCl with a longitudinal slot, a longitudi nalexternally projecting metal feed regulating strip entering said slot,theportion of said strip exterior to the-main electrode portion having astiffening formation relatively stiiier than said strip where it enterssaid slot. V

4. An arc lamp'electrodehaving a longi tudinal external metal feedregulating strip secured thereto, the said strip-having an electrodeengaging longitudinal portion of substantially uniform 'cross section,and the exterior portion of the said feeding strip being given astiffening formation.

An arc lamp electrode having, in combination with a main electrodeportion provided with a slot having a contracted entrance and aninwardly expanding portion, a continuous longitudinal metal feedregulating strip having a maximum cross sec tion substantially. at itsopposite longitudinal edges and a contracted portion located in saidcontracted portion of said slot, said strip being locked to the mainelectrode portion by the engagement of its inner longitudinal edge withthe enlarged portion of said slot.

' 6. An are lamp electrode having, in combination with a main electrodeportion provided with a slot havlng a contracted entrance and aninwardly expanding portion,

' larged portion of said slot.

7. An arc lamp electrode having-a longitudinal externally projectingmetal feed regulating strip secured thereto and of sub stantiallyuniform thicknessl said strip having an electrode-engaging longitudinalrectilinear portion, and the external portion being laterally stiffenedby corrugations ex tending across said external portion and locatedwholly externally ofthe electrode.

Signed at Boston, in the county of Suffolk and Commonwealth ofMassachusetts dayof October, A. D. 1909. MALCOLM H. BAKER.

WVitnesses: I I v CH R'Lns D. JENNINGS,

JOSHUA D. ROBINSON.

this twentieth Copies of this patent. may be obtained foriive centseach, by addressing the Commissioner of Patents.

' i Washington, D. 0.?" i 7

